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ABSTRACT: Background
The current standard immunosuppressive regimens, calcineurin inhibitors, have diabetogenic and anti-vascularization effects on islet grafts. KRP-203, a sphingosine-1-phosphate functional antagonist, exerts its immunomodulatory function through lymphocyte sequestration. However, the effect of this antagonist on islets is unclear. We examined the effect of KRP-203 on the islet function and vascularization and sought a calcineurin-free regimen for islet allotransplantation.Methods
KRP-203 was administered for 14 d to mice, then diabetogenic effect was evaluated by blood glucose levels and a glucose tolerance test. Static glucose stimulation, the breathing index, and insulin/DNA were examined using isolated islets. Islet neovascularization was evaluated using a multiphoton laser scanning microscope. After islet allotransplantation with either KRP-203 alone, sirolimus alone, or both in combination, the graft survival was evaluated by blood glucose levels and immunohistochemical analyses. A mixed lymphocyte reaction was also performed to investigate the immunologic characteristics of KRP-203 and sirolimus.Results
No significant differences in the blood glucose levels or glucose tolerance were observed between the control and KRP-203 groups. Functional assays after islet isolation were also comparable. The multiphoton laser scanning microscope showed no inhibitory effect of KRP-203 on islet neovascularization. Although allogeneic rejection was effectively inhibited by KRP-203 monotherapy (44%), combination therapy prevented rejection in most transplanted mice (83%).Conclusions
KRP-203 is a desirable immunomodulator for islet transplantation because of the preservation of the endocrine function and lack of interference with islet neovascularization. The combination of KRP-203 with low-dose sirolimus may be promising as a calcineurin-free regimen for islet allotransplantation.
SUBMITTER: Fathi I
PROVIDER: S-EPMC9038237 | biostudies-literature | 2022 May
REPOSITORIES: biostudies-literature
Transplantation 20210701 5
<h4>Background</h4>The current standard immunosuppressive regimens, calcineurin inhibitors, have diabetogenic and anti-vascularization effects on islet grafts. KRP-203, a sphingosine-1-phosphate functional antagonist, exerts its immunomodulatory function through lymphocyte sequestration. However, the effect of this antagonist on islets is unclear. We examined the effect of KRP-203 on the islet function and vascularization and sought a calcineurin-free regimen for islet allotransplantation.<h4>Me ...[more]